The present invention relates to grinding machines and analogous machine tools in general, and more particularly to improvements in apparatus for monitoring the parameters of workpieces which are being treated by one or more grinding lapping, polishing or like wheels. Still more particularly, the invention relates to improvements in surface grinding machines or other types of machine tools which are used to treat rotary workpieces.
It is often desirable to ensure that the quality of finish of the surface of a ground, polished or similarly treated workpiece at least approximates a predetermined value. In accordance with heretofore known proposals, a workpiece which has been treated in a grinding machine (for example, in a circular grinding machine) is monitored in a laboratory subsequent to its removal from the grinding machine. The ground workpiece is cleaned to remove the film of lubricant which normally adheres to the freshly ground surface, and the surface of the thus cleaned workpiece is thereupon monitored in a suitable optical or other testing apparatus. For example, it is known to monitor the quality of finish of the surface of a ground workpiece by directing against the surface a beam of radiation which is reflected by the ground surface and is conveyed to an optoelectrical transducer. The transducer generates signals which are indicative of the quality of finish of the tested surface. Signals which are generated by the transducer are utilized to adjust the grinding machine so as to ensure that workpieces which are treated thereafter are finished to a higher degree of precision. In other words, the grinding machine is adjusted only upon completion of the treatment of that workpiece whose surface has been tested in order to ascertain the quality of its finish. Consequently, each workpiece which is found to be defective must be discarded. The adjustment of grinding machine in response to signals from the transducer can involve a dressing of the working surface of the grinding wheel.